Method of treating tows in tubes



Oct. 11, 1955 J. F. KEGGIN 2,720,442

METHOD OF TREATING TOWS IN TUBES Filed May 23, 1949 Inventor JAMES FARGHER KEGGIN Attorneys 2,120,442 METHOD OF TREATING rows IN TUBES James F. KeggimSeamill, Scotland, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain i v The present invention relates to a method of treating a tow of filaments or threads in a limited space and is particularly concerned with a method of treating in non-tensioned condition a continuous tow of artificial filamentary products with a treating liquid having a specific gravity greater than the specific gravity of the tow.

It has beenfound to be ditficult, e. g. to insolubilise in a satisfactory manner a continuous travelling tow of artificial filamentary products of vegetable seed globulins or phospho-proteins by allowing these products to fall into and accumulate or form folds in insolubilising solutions containing formaldehyde, sodium sulphate and sulphuric acid and of the kind which are of higher specific gravity than the said tow and are contained in a static tank of large but reasonable dimensions. The tow is found to form a compact floating mass difficult for the liquid to penetrate and the top of which is not in contact with the liquid, and to become entangled if a sufficient length is permitted to accumulate in the tank for it to receive the necessary time of treatment in the treating liquid. 1

Unsatisfactory results are also obtained if a tow of such filaments or threads is permitted to drop into and to.form folds in the aforesaid-liquidsfiowing through a static trough .as tangling again results.

According to the present invention the method of treating in a non-tensioned condition a continuous tow of filamentary products with a treating-liquid having a specific gravity greater than the specific gravity of the tow comprises introducing a tow by means of a current of said treating-liquid through a tubular structure portion ending in a portion of preferably progressively increasing width leading to a tubular structure portion substantially wider than the narrowest part of the aforementioned tubular structure, arranging that the necessary length of the upper surface of the said wider tubular structure is at a lower level than the overflow level of the treating liquid and that the speed of the treating liquid through said tubular structures and the inclination upwards in the direction of flow of the said upper surface are such that the desired quantity of tow collects against the said upper surface and that the portion of the tow withdrawn from out of the treating liquid at the exit end of the broader tubular structure has remained in the treating liquid for the desired period of time.

The method of thepresent invention has been found particularly advantageous for the insolubilisation of continuous travelling tows of artificial filamentary products of protein with acidified concentrated saline solutions containing formaldehyde and of the kind which are of higher specific gravity than said tow.

The treating liquid and the tow pass through the narrower bore of the tubular structure at relatively high speed. The speed of the liquid here, which is controlled by the head or dilference in level of the liquid at the entrance to the narrower tube and the exit of the wider tube or alternatively the pumping pressure, must be at least as great as that of the tow at this point. On enter- 2,720,442 Patented Oct. 11, 1955 ing the wider tube the tow folds irregularly and forms a loose column of fibre which moves slowly up the tube against the upper surface. This speed of travel in the wider tube is controlled to some extent by the speed of liquid flow in the wider tube, which depends on the relative bores of the narrower and wider tubes and the initial speed of the tow; and also on the inclination of the wider tube, for the fibre, being less dense than the liquid, tends to slide up the tube. Thus, the time of treatment of the fibre, which is the time taken to traverse the narrower and wider tubes, depends on the above factors controlling the speed of travel, and also on the length of the wider tube, or more accurately, on the length of the column of folded fibre allowed to accumulate in the wider tube before withdrawal.

tube, i. e. the head, is adjusted to be somewhat greater than the tow speed. The bore size of the narrower tube is a matter of convenience. The size of the wider tube is then determined by the required time of treatment. It is possible to vary this time within very wide limits in the same apparatus, as the fibre may be drawn through both tubes with very little accumulation in a fraction of a minute, or may be allowed to accumulate in a longer column, the length of which is determined by the length of the wider tube, so that the time of passage may take many minutes. a

Care has to be taken that the withdrawal of the tow from the treating liquid is in no way adversely atfected by the treating liquid flowing out of the tubular structure of wider width and for this purpose it is desirable to provide said structure at the exit end with a perforated weir or an equivalent acting device.

Preferably the upper surface of said wider tubular structure is inclined at an angle lying between 5 and 30 to the horizontal.

The tubular structure portion having the narrow bore inlet is preferably of progressively increasing width, ap

proaching or equal to the width of the tubular structure,

Example A matured caustic soda solution of groundnut globulin prepared from a solution containing 20 parts peanut globulin, 1.25 parts sodium hydroxide, 1.0 part of sodium sulphite and 77.75 parts water is extruded into the coagulating bath containing 200 gm./l. sodium sulphate and 20 gm./l. sulphuric acid. The resulting tow of 15,000 filaments each of 3 to 4 denier is taken up on godets having a peripheral speed of 30 metres per minute and stretched by passing on to godets having a peripheral speed of 45 metres per minute.

The tow is then relaxed in a bath containing 300 gms./l. sodium chloride, 30 gms./l. sodium sulphate and not more than 3 gms./l. sulphuric acid at 20 C., removed from this bath by godets and passed into a setting bath containing 300 gms./l. sodium chloride, 30 gms./l. sodium sulphate, not more than 3 gms./l. sulphuric acid, and 5 gms./l. of formaldehyde, at 65 C. From this bath the tow 1 is removed by a godet 2 of peripheral speed 26 metres per minutes and passes on to a godet 3 of peripheral speed 29 metres per minute, and then vertically downwards into the constant level feed cone 4, where it is For a tow of given size and rate of delivery, the speed of liquid in the narrower picked up by the hardening liquid which enters the feed cone through a pipe 5 and is then carried through the tube 6 and the glass cone 7 into the inclined tube 8. The tube 6 is of inch diameter and the glass cone 7 is 4 inches in diameter at the open end. 'The composition of the hardening liquid is 111 gms./l. sodium chloride, 405 gins/l. sodium sulphate, 13 gms./l. formaldehyde and 3-03 gins/l. sulphuric acid, and it enters the tube 8 at 90 C. and overflows at 88 C. The speed of the liquid flow through tube 6 is controlled by the dilference in levels of the liquid at the inlet cone 4 and the overflow at the exit end of the tube 8, which in this case is 4 inches. The tube 8 is of glass, 6 inches in diameter and 6 feet long, inclined so that the exit end is raised 14 inches above the inlet end. At the exit end of the tube 8 is attached a perforated lip 9 made of lead, which raises the level of the liquid in the tube 8 and allows it to how away without giving rise to local regions of high speed flow. The speed of the tow at feed cone 4 is 29 metres per minute. 8 through the funnel 7 the tow forms a loose column about 4 feet long against the upper surface of the tube 8 filling roughly about three quarters of the cross sectional area and is then removed at the exit end by a godet 10. The peripheral speed of this godet is adjusted to 21 metres per minute so that the time of passage through the tube 8 is constant and around 3 minutes, which is sufficient to insolubilise the protein fibre.

-I claim:

1. A method of treating in a non-tensioned condition without tangling a continuoustow of artificial protein filaments which comprises introducing a tow of said filaments into the upper end of a longitudinally confined downwardly inclined treating zone of relatively small cross-sectional area, propelling said tow with a current of treating and carrying liquid having a specific gravity greater than the specific gravity of said tow through said first treating zone downwardly from the upper end thereof, said liquid completely filling said zone, moving said liquid together with the tow therein out of said first treating zone and directly therefrom into the lower end of a second longitudinally confined upwardly inclined treating zone of relatively large cross-sectional area in comparison with said first zone, said liquid completely On entering the inclined tube filling said second zone, carrying said tow through said second zone by nroving said liquid in a non turbul'ent condition through said second treating zone and withdrawing said tow from the upper end of said second treating zone.

2. A method as recited-in claim 1 in which said downwardly directed narrow confined zone is substantially vertical and in which said upwardly inclined elongated confined zone has a cross-sectional area several times greater than the cross-sectional area of said narrow zone to insure an absence of turbulence in the major portion of said upwardly inclined zone.

3. A method as recited in claim '1 in which the treating liquor is an acidified concentrated saline solution containing formaldehyde.

4. A method as recited in claim 1 in which the time of treatment is varied by adjusting the velocity of the treating liquid and the angle of inclination of said upwardly inclined zone.

References Cited in the file of this patent UNITED STATES PATENTS 430,817 Anderson June 24, 1890 1,403,126 Lyth Jan. '10, 1922 1,702,535 Cole Feb. 19, 1929 1,825,478 Rowley Sept. 29, 1931 1,871,100 Walton et-al Aug. 9, 1932 1,913,601 Leppin "a June 13, 1933 1,917,065 Rusden July 4, 1933 2,131,409 Nai Sept. 27, 1938 2,149,708 Von-Recklinghausen Mar. 7, 1939 2,156,090 Hinnekens Apr. 25, 1939 2,267,117 Mann Dec. 23, 1941 2,313,006 Ufnows'ki Mar. 2, 1943 2,371,579 Cole Mar; 13, 1945 2,377,434 Lyem June 5, 1945 2,333,358 Worrnell Aug. 21, 1945 2,493,740 Adams Jan. 10, 1950 FOREIGN PATENTS 439,153 France Apr. 1, 1912 13,626 Great Britain of 1889 467,257

Great Britain 1937 

1. A METHOD OF TREATING IN A NON-TENSIONED CONDITION WITHOUT TANGLING A CONTINUOUS TOW OF ARTIFICAL PROTEIN FILAMENTS WHICH COMPRISES INTRODUCING A TOE OF SAID FILAMENTS INTO THE UPPER END OF A LONGITUDINALLY CONFINED DOWNWARDLY INCLINED TREATING ZONE OF RELATIVELY CONFINED CROSS-SECTIONAL AREA, PROPELLING SAID TOW WITH A CURRENT OF TREATING AND CARRYING LIQUID HAVING A SPECIFIC GRAVITY GREATER THAN THE SPECIFIC GRAVITY OF SAID TOW THROUGH SAID FIRST TREATING ZONE DOWNWARDLY FROM THE UPPER END THEREOF, SAID LIQUID COMPLETELY FILLING SAID ZONE, MOVING SAID LIQUID TOGETHER WITH THE TOW THEREIN OUT OF SAID FIRST TREATING ZONE AND DIRECTLY THEREFROM INTO THE LOWER END OF A SEOCND LONGITUDINALLY CONFINED UPWARDLY INCLINED TREATING ZONE OF RELATIVELY LARGE CROSS-SECTIONAL AREA IN COMPARISON WITH SAID FIRST ZONE, SAID LIQUID COMPLETELY FILLING SAID SECOND ZONE, CARRYING SAID TOW THROUGH SAID SECOND ZONE BY MOVING SAID LIQUID IN A NON-TURBULENT CONDITION THROUGH SAID SECOND TREATING ZONE AND WITHDRAWING SAID TOW FROM THE UPPER END OF SAID SECOND TREATING ZONE. 